The present invention refers to a coffee maker for brewing coffee powder contained in a cartridge, comprising a brewing chamber adapted to receive a coffee powder cartridge, at least one means for punching the coffee powder cartridge, and a pump for feeding hot brewing water into the brewing chamber.
Coffee makers of this kind are used predominantly in homes, i.e. are designed for household use. As compared to conventional coffee makers with a grinder for grinding whole coffee beans, a fundamental advantage of the above mentioned coffee maker may be seen in the fact that a qualitatively high grade coffee beverage can be prepared by using pre-packed coffee powder cartridges, the more so as the coffee powder is optimally ground and kept in the cartridge in an airtight manner. Moreover, such coffee makers are less subject to contamination by coffee powder.
For brewing the coffee powder contained in the cartridge, either manually operated or semi-automatic as well as fully automatic coffee makers are used. Usually, in a manually operated coffee maker, the cartridge is inserted into a cartridge holder that in turn is inserted into the coffee maker. In the semi-automatic coffee makers, the cartridge is inserted into a cartridge retainer or directly into the brewing chamber of the machine, whereby the brewing chamber is manually closed by means of a central lever mechanism. In a fully automatic coffee maker, however, the cartridge is removed from a cartridge magazine and automatically inserted into the brewing chamber; after the brewing operation, the cartridge is removed from the brewing chamber and discarded into a trash receptacle without any intervention of the operator.
All these above mentioned species of coffee maker usually comprise a hollow so-called brewing spike provided with radial outlet openings for injecting brewing water into the cartridge that is also adapted to punch the bottom and the cover, respectively, of the cartridge. Also known are manually operated coffee makers in which the cartridge retainer is provided with a plurality of embossments located on an outlet grate; these embossments break open the cover of the cartridge as soon as brewing water is injected into the cartridge from the opposite side thereof and the cartridge is pressed against the embossments under the influence of the hydraulic overpressure created by the pressurized brewing water. During the subsequent brewing operation, the brewing water is injected into the cartridge by means of the brewing spike, with the result that is flows under pressure through the coffee powder contained in the cartridge and escapes from the cartridge through the opening created by the embossments.
Independent of the fact whether it is a manually operated coffee maker or a semi-automatic or a fully automatic machine, the coffee maker is designed and adapted to the cartridge so as to produce a coffee beverage having froth on its surface; that froth usually is considered as a characteristic of a good coffee beverage.
Even if great efforts have been taken to ensure that the prepared coffee beverage has durable froth on its surface, in certain countries the desire arises to prepare also conventional coffee in the sense of a filter coffee by means of these coffee makers. In place of the expression “filter coffee”, also the expression “gentle coffee” is used.